This invention relates to a catalyst for hydrotreatment and hydrodemetalation of hydrocarbonaceous feedstocks. More particularly, this invention relates to catalysts and catalyst supports fabricated from halloysite.
Impurities such as metals, sulfur and nitrogen are contained in hydrocarbonaceous materials including crude oils, heavy oils, cracked oils, deasphalted oils, residual oils, shale oils, coal and partially liquefied coal and the like. These impurities are discharged into the atmosphere when the hydrocarbon is burned, creating a major source of pollution. They also tend to rapidly foul catalysts used for processing of the hydrocarbon or treating the exhaust from combusted hydrocarbons. The removal of these undesirable impurities as early as possible in the processing of the hydrocarbonaceous materials is therefore highly desirable.
When metals such as nickel, iron and vanadium are present, they tend to deposit on the interior surface of the pores of hydroprocessing catalysts, tending to plug the pore mouths thereby reducing activity. It is desirable, therefore, that a substantial volume of the pores have a pore mouth diameter greater than 200 Angstroms. The majority of the pores should be preferably smaller than about a 1000 Angstroms because large pores tend to decrease the mechanical crush strength of the catalyst bodies, and also decrease surface to volume ratios.
Catalysts that effectively treat asphaltene containing fractions are desirable because many known crude oil reserves worldwide are high in asphaltenes. Additionally, various synthetic fuel processes tend to create fractions high in asphaltenes.
Catalysts containing clay materials have been suggested for hydroprocessing heavy hydrocarbon feeds. For example, U.S. Pat. No. 4,152,250 to Inooka suggests the use of a catalyst containing the mineral sepiolite (Meershaum), a fibrous magnesium silicate clay and transition metals and/or Group II-B metals. Another clay which has been suggested is halloysite. Halloysite is an aluminum silicate clay that frequently occurs naturally in a rod like form. The basic formula is Al.sub.2 Si.sub.2 O.sub.5 (OH).sub.4.
In U.S. Pat. No. 4,098,696, a synthesis of the plate form of halloysite is disclosed. In U.S. Pat. No. 3,891,541 a demetalation catalyst is disclosed that is formed from halloysite and alumina. The pore structure contains pores with a diameter of between about 180 Angstroms to about 300 Angstroms. The pore diameters are said to be an artifact of the alumina.